1. Field of the Invention
The present invention relates to a method, of adjusting a binocular type device comprising a pair of eyeglasses and fitted with an optical imager for each eye that serves to project image or multimedia type information.
2. Description of Related Art
The term “binocular” means a display that provides a virtual, image for each eye of the wearer.
An example of a prior art binocular display is shown in FIG. 1.
In that display, the optical imagers 1, 2 are designed to shape light beams coming from a miniature screen 3, 4 of an electronic and optical system for generating light beams. Each optical imager directs light beams towards a corresponding eye O1, O2 of the wearer so as to enable the information content to be viewed.
In such a display, an electronic signal carrying information is delivered to each miniature screen by a cable. From this signal, the miniature screen, illuminated by a backlight, generates a pixilated image corresponding to the information. By way of example, it is possible to use a “KOPIN Cyberdisplay 320 color” screen that, generates images of 320×240 pixels having dimensions of 4.8 millimeters (mm)×3.6 mm. The screens are put into reference positions relative to the optical imagers by a mechanical interface. A protective shell protects the assembly completely or in part.
In order to obtain good viewing with such a display, it is important for the image I1 seen by the left eye and the image I2 seen by the right eye to be superposed.
At present, in order to align these left and right images of a binocular display, there is a step during the assembly method that consists in physically moving the miniature screens 3, 4 perpendicularly to the optical axes A1, A2 of the optical imagers, and in turning them in their planes so as to move at least one of the virtual images in corresponding manner, thereby causing the left and right images to be brought into superposition.
More precisely, the prior art alignment method consists in fastening the first screen, e.g. the left screen 3, relative to the left imager 1, typically by adhesive, and then in moving the right screen 4 perpendicularly to the optical axis A2 of the right imager and possibly turning it in its plane so as to bring the right image into coincidence with the left image, and once this has been done, locking it in the aligned position by means of adhesive.
That type of solution requires shells or casings to be designed that enable miniature screens to be moved transversely in this way for adjustment purposes, and also a system for providing temporary locking prior to final fastening by adhesive.
That method requires a step that is lengthy and difficult from a handling point of view, which in practice makes it difficult to obtain good productivity.
Finally, and above all, that type of adjustment is fiddly since it requires micrometric movements of the screen and thus a mechanical arrangement for micrometric adjustment that is complex in terms of its structure and its implementation.
Patent document US 2003/0184868 discloses a method of adjusting a binocular display that comprises, for each eye of the wearer, an optical imager for shaping light-beams corresponding to an image emitted by a beam generator device and for directing them to each of the wearer's eyes so as to enable information content contained in a virtual image to be viewed, that display being associated with a pair of eyeglasses having two lenses supported by a frame. According to that document, the arrangement forming the imager may be moved in order to perform the adjustment.
That type of adjustment is likewise fiddly since it requires micrometric movements of the imager and thus a mechanical arrangement for micrometric adjustment that is complex as to its structure and its implementation.
Patent document WO 2007/125257 thus envisages proceeding with the alignment of the right and left images without any physical movement of the miniature screens, but rather by moving the image that is emitted on the screen electronically, so as to obtain an adjusted position for the image on the screen that corresponds to both virtual images being superposed.